Ashley Stueck

Hepatocyte buds derived from progenitor cells repopulate regions of parenchymal extinction in human cirrhosis.

Repair of cirrhotic livers occurs, in part, by repopulation with hepatocytes through the stem/progenitor pathway. There remain many uncertainties regarding this pathway. Hepatocyte “buds” occurring in broad septa are hypothesized to be the anatomic manifestation of this pathway. Our purpose was to define a morphologic sequence of bud maturation to allow a quantitative measure of the importance of the stem/progenitor pathway in humans. Histologic sections from 37 liver resection specimens were stained with trichrome, epithelial cell adhesion molecule (EpCAM), K19, CD34, glutamine synthetase (GS), and Ki‐67. Specimens were stratified by etiology (10 biliary, 22 nonbiliary, five controls) and stage. Buds were defined as clusters of hepatocytes within septa. Five levels of bud maturation (0‐4) were defined by the progressive increase in hepatocyte progeny relative to cholangiocytes. Level 0 single‐cell buds are K19+/GS+/EpCAM+/Heppar1−. In level 1, the progeny are morphologically hepatocytes (K19−/GS+/EpCAM+/Heppar1+). In level 2‐4 buds, hepatocytes increase and become progressively GS− and EpCAM−. Associated endothelium is CD34+ in level 1‐2 buds and becomes CD34− near hepatic veins in level 3‐4 buds. Progeny of the bud sequence may represent up to 70% of hepatocytes (immaturity index of 70%). In biliary disease, bud number is reduced in association with duct loss and cholestatic destruction of nascent buds. Conclusions: The stem/progenitor pathway, manifested anatomically by the bud sequence, is a major mechanism for repopulation of cirrhotic livers. The bud sequence reveals some critical features of hepatic morphogenesis, including that 1) the majority of distal cholangiocytes have stem‐like properties, and 2) availability of bile ducts and/or venous drainage are limiting factors for regeneration. (Hepatology 2015;61:1696–1707)

Mixed hepatocellular cholangiocarcinoma tumors: Cholangiolocellular carcinoma is a distinct molecular entity

BACKGROUND & AIMS Mixed hepatocellular cholangiocarcinoma (HCC-CCA) is a rare and poorly understood type of primary liver cancer. We aimed to perform a comprehensive molecular characterization of this malignancy. METHODS Gene expression profiling, DNA copy number detection, and exome sequencing using formalin-fixed samples from 18 patients with mixed HCC-CCA were performed, encompassing the whole histological spectrum of the disease. Comparative genomic analysis was carried out, using independent datasets of HCC (n=164) and intrahepatic cholangiocarcinoma (iCCA) (n=149). RESULTS Integrative genomic analysis of HCC-CCAs revealed that cholangiolocellular carcinoma (CLC) represents a distinct biliary-derived entity compared with the stem-cell and classical types. CLC tumors were neural cell adhesion molecule (NCAM) positive (6/6 vs. 1/12, p<0.001), chromosomally stable (mean chromosomal aberrations 5.7 vs. 14.1, p=0.008), showed significant upregulation of transforming growth factor (TGF)-β signaling and enrichment of inflammation-related and immune response signatures (p<0.001). Stem-cell tumors were characterized by spalt-like transcription factor 4 (SALL4) positivity (6/8 vs. 0/10, p<0.001), enrichment of progenitor-like signatures, activation of specific oncogenic pathways (i.e., MYC and insulin-like growth factor [IGF]), and signatures related to poor clinical outcome. In the classical type, there was a significant correlation in the copy number variation of the iCCA and HCC components, suggesting a clonal origin. Exome sequencing revealed an average of 63 non-synonymous mutations per tumor (2 mean driver mutations per tumor). Among those, TP53 was the most frequently mutated gene (6/21, 29%) in HCC-CCAs. CONCLUSIONS Mixed HCC-CCA represents a heterogeneous group of tumors, with the stem-cell type characterized by features of poor prognosis, and the classical type with common lineage for HCC and iCCA components. CLC stands alone as a distinct biliary-derived entity associated with chromosomal stability and active TGF-β signaling. LAY SUMMARY Molecular analysis of mixed hepatocellular cholangiocarcinoma (HCC-CCA) showed that cholangiolocellular carcinoma (CLC) is distinct and biliary in origin. It has none of the traits of hepatocellular carcinoma (HCC). However, within mixed HCC-CCA, stem-cell type tumors shared an aggressive nature and poor outcome, whereas the classic type showed a common cell lineage for both the HCC and the intrahepatic CCA component. The pathological classification of mixed HCC-CCA should be redefined because of the new molecular data provided.

Hepatocellular Carcinoma Arising in an HNF-1α-Mutated Adenoma in a 23-Year-Old Woman with Maturity-Onset Diabetes of the Young: A Case Report.

Hepatocyte nuclear factor-1α mutated hepatocellular adenomas (H-HCA) are thought to have no to minimal malignant potential. This report describes a 23-year-old woman with maturity-onset diabetes of the young who developed a 12.5-cm hepatic mass with a radiographically and pathologically distinct 3.0-cm region. Histologically and immunohistochemically, the bulk of the mass was an H-HCA with extensive pseudoglandular formation and only focal steatosis. The 3.0-cm nodule showed small cell change, thickened hepatocyte plates, pleomorphic and hyperchromatic nuclei, reticulin loss, and stromal and vascular invasion, diagnostic of hepatocellular carcinoma (HCC). Immunohistochemically, increased expression of glutamine synthetase in tumor cells and CD34 expression in sinusoidal endothelial cells were seen in the HCC component. Nuclear expression of β-catenin, and exon 3 of CTNNB1 and TERT promoter mutations were absent in this case. Thus, we report a HCC arising in an H-HCA; although cases appear exceedingly rare, they reinforce the potential of H-HCA for malignant transformation.

An Unusual Cause of Acute Liver Failure: Three Cases of Hemophagocytic Lymphohistiocytosis Presenting at a Transplant Center

Acquired hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening disorder of the immune system. Hemophagocytic lymphohistiocytosis has been associated with infections, autoimmune disorders, and malignancy. This case series describes three patients admitted to an academic liver transplant center from February 2014 to February 2015 with acute liver failure (ALF) who were ultimately diagnosed with HLH. All cases were female patients (44 to 53 years of age) transferred for workup of ALF. All developed fevers and cytopenias and underwent rapid evaluation for liver transplant by a multidisciplinary team. A complete workup for ALF was negative for intrinsic liver disease and none had significant alcohol or toxin exposure. The patients had liver biopsies showing diffuse lobular necroinflammation, of which two had evidence of hemophagocytosis on histopathology. The diagnosis of HLH was made by bone marrow biopsy featuring histiocytes with hemophagocytosis. All cases were treated with chemotherapy, but died during their hospitalization. Hemophagocytic lymphohistiocytosis can present as ALF in adult patients. Given the low success rate of treatment, early diagnosis is critical. Therefore, a high degree of suspicion should be exercised in patients with unexplained ALF.

cHCC-CCA: Consensus terminology for primary liver carcinomas with both hepatocytic and cholangiocytic differentation

Primary liver carcinomas with both hepatocytic and cholangiocytic differentiation have been referred to as “combined (or mixed) hepatocellular‐cholangiocarcinoma.” These tumors, although described over 100 years ago, have attracted greater attention recently because of interest in possible stem cell origin and perhaps because of greater frequency and clinical recognition. Currently, because of a lack of common terminology in the literature, effective treatment and predictable outcome data have been challenging to accrue. This article represents a consensus document from an international community of pathologists, radiologists, and clinicians who have studied and reported on these tumors and recommends a working terminology for diagnostic and research approaches for further study and evaluation. Conclusion: It is recommended that diagnosis is based on routine histopathology with hematoxylin and eosin (H&E); immunostains are supportive, but not essential for diagnosis. (Hepatology 2018;68:113‐126).

A pilot study of ultra-deep targeted sequencing of plasma DNA identifies driver mutations in hepatocellular carcinoma

Cellular components of solid tumors including DNA are released into the bloodstream, but data on circulating-free DNA (cfDNA) in hepatocellular carcinoma (HCC) are still scarce. This study aimed at analyzing mutations in cfDNA and their correlation with tissue mutations in patients with HCC. We included 8 HCC patients treated with surgical resection for whom we collected paired tissue and plasma/serum samples. We analyzed 45 specimens, including multiregional tumor tissue sampling (n = 24), peripheral blood mononuclear cells (PMBC, n = 8), plasma (n = 8) and serum (n = 5). Ultra-deep sequencing (5500× coverage) of all exons was performed in a targeted panel of 58 genes, including frequent HCC driver genes and druggable mutations. Mutations detected in plasma included known HCC oncogenes and tumor suppressors (e.g., TERT promoter, TP53, and NTRK3) as well as a candidate druggable mutation (JAK1). This approach increased the detection rates previously reported for mutations in plasma of HCC patients. A thorough characterization of cis mutations found in plasma confirmed their tumoral origin, which provides definitive evidence of the release of HCC-derived DNA fragments into the bloodstream. This study demonstrates that ultra-deep sequencing of cfDNA is feasible and can confidently detect somatic mutations found in tissue; these data reinforce the role of plasma DNA as a promising minimally invasive tool to interrogate HCC genetics.

Feasibility and reproducibility of liver surface nodularity quantification for the assessment of liver cirrhosis using CT and MRI

Purpose To assess intra-observer, inter-observer and inter-modality (CT vs. MRI) reproducibility of liver surface nodularity (LSN) scores measured with software used for detection of liver fibrosis. Methods This IRB-approved retrospective study included patients with both abdominal CT and MRI within 6 months of histopathologic sampling. Two independent observers used post-processing software to quantify LSN scores on axial non-contrast CT (NCT), axial contrast-enhanced CT (CECT), axial T2-weighted (T2W) HASTE, and axial and coronal post-gadoxetic acid T1-weighted (T1W) images obtained during the hepatobiliary phase (HBP). Ten slices were used to acquire the LSN scores. Intra-observer, inter-observer, and inter-modality (CT vs. MRI) reproducibility were assessed with intraclass correlation coefficient (ICC) and coefficients of variability (CV). Accuracy for detection of cirrhosis was evaluated for each technique. Results 26 patients (M/F 19/7, mean age 57 years), including 7 with cirrhosis (26.9%), were assessed. Technical failure occurred with NCT (1/23, 4.3%) and T2 HASTE (8/28, 28.6%). Intra-observer reproducibility was excellent for NCT, CECT, axial and coronal T1W HBP [ICC ≥ 0.92, CV ≤ 8%]. Inter-observer reproducibility was also excellent for NCT and CECT (ICC ≥ 0.95, CV ≤ 7.3%) and for coronal T1W HBP (ICC = 0.84, CV = 5.6%). There was fair to moderate agreement between CT and MRI (ICC 0.20–0.44). There were significant differences in mean LSN scores between non-cirrhotic and cirrhotic patients with NCT (2.6 vs. 4.2, p = 0.04) and T1W HBP (3.7 vs. 4.6; p = 0.01) images, with AUCs of 0.81 and 0.82, respectively. Conclusions LSN measurement is highly reproducible with NCT and post-contrast T1W HBP on MRI, with different results obtained between CT and MRI.

Lymphoepithelioma-Like Carcinoma in Liver

Liver cancer, primarily encompassing hepatocellular carcinoma and intrahepatic cholangiocarcinoma, has become the second leading cause of worldwide cancer-related death during the past two decades. Lymphoepithelioma-like carcinomas (LELCs) are defined as tumors composed of undifferentiated epithelial cells with a prominent lymphoid infiltrate, and can arise in the liver as hepatocellular or cholangiocarcinoma forms. Patients with liver LELC display distinctive demographics and tumor characteristics. LELCs also appear to be associated with strikingly better outcomes compared to typical liver cancers, with 5-year survival rates of 57% to 100% versus 12% to 68%, respectively. Liver LELCs represent a unique model of immune response in liver cancer. Data on LELCs of the liver remain limited, and future comprehensive studies are needed to further elucidate this disease, which could ultimately offer precious insights for immunotherapeutic strategies in liver cancer.

Detection of liver fibrosis using qualitative and quantitative MR elastography compared to liver surface nodularity measurement, gadoxetic acid uptake, and serum markers

Multiparametric magnetic resonance imaging (mpMRI) combining different techniques such as MR elastography (MRE) has emerged as a noninvasive approach to diagnose and stage liver fibrosis with high accuracy allowing for anatomical and functional information.

Evaluation of HCC response to locoregional therapy: Validation of MRI-based response criteria versus explant pathology

BACKGROUND AND AIMS This study evaluates the performance of various magnetic resonance imaging (MRI) response criteria for the prediction of complete pathologic necrosis (CPN) of hepatocellular carcinoma (HCC) post locoregional therapy (LRT) using explant pathology as a reference. METHODS We included 61 patients (male/female 46/15; mean age 60years) who underwent liver transplantation after LRT with transarterial chemoembolization plus radiofrequency or microwave ablation (n=56), or 90Yttrium radioembolization (n=5). MRI was performed <90days before liver transplantation. Three independent readers assessed the following criteria: RECIST, EASL, modified RECIST (mRECIST), percentage of necrosis on subtraction images, and diffusion-weighted imaging (DWI), both qualitative (signal intensity) and quantitative (apparent diffusion coefficient [ADC]). The degree of necrosis was retrospectively assessed at histopathology. Intraclass correlation coefficient (ICC) and Cohens kappa were used to assess inter-reader agreement. Logistic regression and receiver operating characteristic analyses were used to determine imaging predictors of CPN. Pearson correlation was performed between imaging criteria and pathologic degree of tumor necrosis. RESULTS A total of 97HCCs (mean size 2.3±1.3cm) including 28 with CPN were evaluated. There was excellent inter-reader agreement (ICC 0.77-0.86, all methods). EASL, mRECIST, percentage of necrosis and qualitative DWI were all significant (p<0.001) predictors of CPN, while RECIST and ADC were not. EASL, mRECIST and percentage of necrosis performed similarly (area under the curves [AUCs] 0.810-0.815) while the performance of qualitative DWI was lower (AUC 0.622). Image subtraction demonstrated the strongest correlation (r=0.71-0.72, p<0.0001) with pathologic degree of tumor necrosis. CONCLUSIONS EASL/mRECIST criteria and image subtraction have excellent diagnostic performance for predicting CPN in HCC treated with LRT, with image subtraction correlating best with pathologic degree of tumor necrosis. Thus, MR image subtraction is recommended for assessing HCC response to LRT. LAY SUMMARY The assessment of hepatocellular carcinoma (HCC) tumor necrosis after locoregional therapy is essential for additional treatment planning and estimation of outcome. In this study, we assessed the performance of various magnetic resonance imaging (MRI) response criteria (RECIST, mRECIST, EASL, percentage of necrosis on subtraction images, and diffusion-weighted imaging) for the prediction of complete pathologic necrosis of HCC post locoregional therapy on liver explant. Patients who underwent liver transplantation after locoregional therapy were included in this retrospective study. All patients underwent routine liver MRI within 90days of liver transplantation. EASL/mRECIST criteria and image subtraction had excellent diagnostic performance for predicting complete pathologic necrosis in treated HCC, with image subtraction correlating best with pathologic degree of tumor necrosis.